So My LMP Was On The 23rd Of September But

So my LMP was on the 23rd of September but I have a 36 day cycle and sometimes I skip a month. I had sex on October 3rd we used a condom, but before I gave him oral sex and there was some sperm on his skin (at the bottom of the penis) is there any way I could be pregnant? I've been cramping and really bloated and been feeling nauseas but haven't thrown up. I took a HPT and it came up positive, but I took another one and it said negative so which one would I pay attention to? how soon can I go to a clinic to get tested?